<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <!-- 编写函数has(arr , 60) 判断数组中是否存在60这个元素，返回布尔类型 -->
    <script>
      var arr = [10, 20, 30, 60];
      function has(arr, n) {
        for (var i = 0; i < arr.length; i++) {
          if (arr[i] == n) {
            return true;
          }
        }

        return false;
      }

      console.log(has(arr, 60));
    </script>
  </body>
</html>
